Who said prog rock was dead? Well, quite a few people actually. And they're probably right in many ways. Whilst 'Octahedron' is undoubtedly an album of some quality, it sidesteps being filed in that most obvious of places - O for outdated - by managing not to be too typical of the genre.

Opener 'Since We've Been Wrong' does kick things off with an almost inaudible ambience before slipping into a melodic downbeat section that suggests medievalism, but the album as a whole can be seen to be a movement away from the prog stereotypes alluded to in the first few minutes. That said, the questionable artwork is still here. And expectant fans can find some pretty standard Volta fare inside, with the aforementioned opener eventually kicking into guitars and drums, all carrying the lackadaisical pace forward over pseudo-Santana guitar riffs.

The US outfit, now on their fifth outing, do pick up the pace at times. The unnerving, yet intelligently chart-friendly 'Teflon', and the excellent, early Chili Peppers-without-the-funk-but-with-the-metal 'Cotopaxi' offer the best examples of this. The largest difference here is that, with a few exceptions, the pure experimentalism has waned, as has the reliance on heavy rock numbers to make the album 'powerful'. It's the downtempo, though still overtly accessible, tracks that win out in the end.

Tunes with track names such as 'Halo Of Nebutals' and 'With Twilight As My Guide' may sound like something from a Spinal Tap set list, but it doesn't stop them being damn good songs. The former is pleasingly reminiscent of Faith No More, the latter opting for more of a 'Stairway To Heaven' approach; gentle guitar melodies swoon, whilst Cedric Bixler-Zavala's vocals cry passionate, mystical lyrics.

Without question there is talent abound here, the only troubling point is answering if this sound can hold its own further into the 21st Century. There are few genres that simultaneously do not scare, yet are as specialist. Here's hoping it can. Odd as it may be, it's a far cry from production line pop, mainstream metal or economically viable electronica.